• Title/Summary/Keyword: isothermal model

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Numerical study on thermophoretic deposition of highly absorbing emitting particles suspended in a non-isothermal two-phase flow system (비등온 이상유동 시스템에 부유된 고흡수, 방사하는 입자의 열환산적 부착현상에 대한 수치적 연구)

  • Yoa, S. J.
    • Journal of the korean Society of Automotive Engineers
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    • v.11 no.5
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    • pp.90-100
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    • 1989
  • 본 논문은 이상유동 시스템에 부유도니 슈트, 미분탄과 같은 고 흡수, 방사하는 입자에 의한 열 확산 현상에 대한 복사효과를 수치적으로 검토하였다. 가스, 입자유동의 지배방정식들은 오일러 관점의 two-fluid model 의 근간에서 수행되었으며, 에너지 방정식의 비선형 복사생성항은 P-1 근사방법에 의해 계산되었다. 복사효과가 증가될 때에 열확산적 입자의 벽면에 대한 부착율은 상당히 낮아짐을 보였으며 열확산 현상의 스토크스 수에 따른 효과도 고려되었다.

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A Study on the Effects of Temperature Rise and Turbulence on the Performance of Large Tilting Pad Journal Bearings (대형 틸팅패드 저어널베어링의 성능에 미치는 온도상승 및 난류의 효과에 관한 연구)

  • 하현천;김경웅
    • Tribology and Lubricants
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    • v.9 no.1
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    • pp.22-31
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    • 1993
  • The thermohydrodynamic performance of large tilting pad journal bearings is analyzed, taking into account the three dimensional variation of lubricant viscosity. The eddy viscosity model based on wall formula is applied. The effects of temperature rise and turbulence on the bearing performance are studied in comparision with the isothermal or the laminar analysis. It is shown that these effects have significant influence on temperature distribution, load capacity and power loss of the bearing.

The Grain Growth Mechanism of Sm123 Superconductor in Melt-Textured Growth Method (용융-응고법으로 제조된 Sm123 초전도체의 결정성장 기구)

  • 한상철;성태현;한영희;이준성;김상준
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2001.02a
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    • pp.9-12
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    • 2001
  • The microstructure evolution and the peritectic solidification of Sm$Ba_{2}$$Cu_{3}$ $O_{7-\delta}$ superconducting materials during the isothermal annealing were studied over the temperature range 1030-$1060^{\circ}C$ The faceted growth of the peritectic phase and its dependence upon Sm-diffusion in the liquid phase are discussed. A growth model is proposed to explain the growth shape of Sm123 crystals.

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Non-isothermal Effect on the Flow Behavior of Polymer Melts in a Coextrusion Die (고분자의 Coextrusion에서 유동에 대한 비등온 효과)

  • 정인재
    • The Korean Journal of Rheology
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    • v.6 no.2
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    • pp.129-138
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    • 1994
  • 공압출되는 sheet die에서 고분자 물질의 비등온 유동유동을 수치모사하였다. 유변학 적 식으로 power-law model을 사용하였고, 격자생성법을 이용한 유한차분법을 사용하였다. 수치계산을 통해 수축채널에서의 온도 분포를 구해보고 점도가 채널에서의 온도 분포를 구 해 보고 점도가 채널에서의 압력강하 및 신장속도에 미치는 영향을 알아보았다. 압력강하는 외부 유체의 점도 및 heat dissipation의 영향을 크게 받았다. 신장속도는 외부 유체의 점도 가 증가함에 따라 커진 반면 내부 유체의 점도가 증가함에 따라 커진반면, 내부 유체의 점 도증가에 따라 감소하였고, heat dissipation에 의해 증가하였다.

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Fundamental Study on a Distillation Separation of a LiCl-KCl Eutectic Salt from Rare Earth Precipitates (희토류 침전물로부터 LiCl-KCl 공융염의 증류 분리에 관한 기초연구)

  • Yang, Hee-Chul;Eun, Hee-Chul;Kim, In-Tae
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.8 no.1
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    • pp.65-70
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    • 2010
  • The distillation rate on LiCl-KCl eutectic salt under different vacuums from 0.5-50 mmHg was first investigated by using both a non-isothermal and a isothermal thermogravimetric (TG) analysis. Based on the non-isothermal TG data, distillation rate equations as a function of the temperature could be derived. Calculated flux by these model flux equations was in agreement with the distillation rate obtained from isothermal TG analysis. A distillation rate of $10^{-4}-10^{-5}$ mole $cm^{-2}sec^{-1}$ is obtainable at temperatures less than 1300K and vacuums of 0.5-50 mmHg. About a 99% salt distillation efficiency was obtained after an hour at a temperature above 1150 K under 50 mmHg in a small scale distillation test system. An increase in the vaporizing surface area is relatively effective for removing residual salt in the remaining particles, when compared to that for the vaporizing time. Over 99.95% of total distillation efficiency was obtained for a 1-h distillation operation by increasing the inner surface area from $4.52cm^2$ to $12.56cm^2$.

Effect of thermal laser pulse in transversely isotropic Magneto-thermoelastic solid due to Time-Harmonic sources

  • Lata, Parveen;Kaur, Iqbal;Singh, Kulvinder
    • Coupled systems mechanics
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    • v.9 no.4
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    • pp.343-358
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    • 2020
  • The present research deals with the time-harmonic deformation in transversely isotropic magneto thermoelastic solid with two temperature (2T), rotation due to inclined load and laser pulse. Generalized theory of thermoelasticity has been formulated for this mathematical model. The entire thermo-elastic medium is rotating with uniform angular velocity and subjected to thermally insulated and isothermal boundaries. The inclined load is supposed to be a linear combination of a normal load and a tangential load. The Fourier transform techniques have been used to find the solution to the problem. The displacement components, stress components, and conductive temperature distribution with the horizontal distance are computed in the transformed domain and further calculated in the physical domain using numerical inversion techniques. The effect of angle of inclination of normal and tangential load for Green Lindsay Model and time-harmonic source for Lord Shulman model is depicted graphically on the resulting quantities.

Numerical Modeling of Solid Alkaline Fuel Cell (고체 알칼리 연료전지 모델링)

  • Kim, Kyoungyoun;Sohn, Young-Jun;Choi, Young-Woo;Park, Seok-Hee;Kim, Chang-Soo
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.05a
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    • pp.98.1-98.1
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    • 2011
  • We present here an isothermal, one-dimensional, steady-state model for a solid alkaline fuel cell (SAFC) with an anion exchange membrane. The conducting ions now move from the cathode to the anode in SAFC. The water is produced at the anode and is also a stoichiometric reactant at the cathode as well as hydrogen and oxygen. In the present model, a net-water-per-proton flux ratio can be predicted and the water transport in the SAFC is explained for various operating conditions.

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An experimental study for the coal particle separator in the pulverizer model with dynamic classifier (Dynamic classifier가 장착된 미분기 모델에서의 석탄 입자 분리 실험)

  • Lee, Gun-Myung;Kim, Hyuk-Je;Kim, Hyeuk-Pill;Kim, Sang-Hyeun;Ha, Jong-Kang
    • Proceedings of the KSME Conference
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    • 2001.11b
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    • pp.688-692
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    • 2001
  • Three-dimensional experimental analyses were conducted in the pulverizer simplified isothermal model. The experimental model was constructed on a 1/3.5 scale of 500MW pulverized coal boiler. The purpose of this study is to investigate the characteristics of coal particle separator and the pressure loss in the pulverizer models with dynamic classifier. Without regards a shape of separator top, the results showed that the increase of dynamic classifier rpm was induced in finer coal particle. But the capacity of total mass per minute was reduced. Also, the increase of dynamic classifier rpm had no effect on total pressure loss, but an increase of inlet velocity was induced that the rise of total pressure loss in the pulverizer models with dynamic classifier.

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Direct Numerical Simulation of the Nucleate Pool Boiling Using the Multiphase Lattice Boltzmann Method : Preliminary Study (다상 격자 볼츠만 방법을 이용한 수조 핵비등 직접 수치 모사: 예비 연구)

  • Ryu, Seung-Yeob;Ko, Sung-Ho
    • The KSFM Journal of Fluid Machinery
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    • v.14 no.6
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    • pp.45-53
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    • 2011
  • Multiphase lattice Boltzmann method (LBM) has been used to simulate the nucleate pool boiling directly. For the phase change model, the thermal model and the Stefan boundary condition were introduced to the isothermal LBM. The phase change model was validated by the bubble growth in a superheated liquid under no gravity. The bubble growth on and departure from a superheated wall has been simulated successfully. The preliminary results showed that the detail process of nucleate pool boiling was in good agreement with the experimental results.